Macroinvertebrates and Water Quality in Oxbow Lakes along the Savannah River

Abstract

Oxbow lakes are the remains of original channels that were cut off from the main river. Being more stagnant than the river, these lakes often differ in many physical, chemical, and biological parameters from the adjacent river. The goal was to compare four Savannah River oxbow lakes – Conyers, Miller, Possum Eddy, and Whirligig – to determine similarities and differences between oxbows with and without existing surface connections during non-flood flows. The comparison focused on water quality parameters and macroinvertebrate abundance and diversity. It is hypothesized that oxbow lakes with an existing surface water connection to the river have greater macroinvertebrate abundance and diversity than disconnected oxbows. Macroinvertebrates were sampled from sediment and other substrates using a petit ponar dredge and d-ring dip-nets, sorted according to EPA protocols, and identified to order or family. The resulting data showed that the most common organism at all sites were insects in the family Chironomidae, followed closely by members of the orders Cladocera, Anostraca, and Hemiptera. Among lakes, Conyer’s Lake (disconnected lake) was dominated by Bivalvia organisms, and Miller Lake (connected lake) was dominated by Hemiptera organisms whereas Chironomidae was the most common macroinvertebrate found in Possum Eddy (disconnected